Electric switch



NOV. 17, 1931. FISHER 1,832,695

ELECTRIC SWITCH Filed March 10, 1928 Fig. 2.

Fig. 3.-

Ir Ihv enfor 24'- Frederick E. Fisher, I 0 by I His ATTor'ne- Patented 17, "1931.

UNITED STATES PATENT OFFDICE FREDERICK E. FISHER, OF SUDBBOOK PARK, MARYLAND, ASBIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK ELECTRIC swrrcn,

My invention relates to improvements in electric switches and more particularly to improvements I in disconnecting switches which are used to isolate electric apparatus and portions of an electric circuit and sometimes to interrupt relatively small amounts of power. Switches of this type are apt to be operated infrequently and where they remain closed for any considerable time corrosion may cause sticking of the contacts;

When used outdoors, ice deposits often have the same efiect. This makes it more or less diflicult to open the switch, particularly if the blade is relatively long, and subjects the various parts to stresses for which due allowance must be made at the sacrifice of an otherwise structural economy. Moreover, with low pressure and large area contacts, sticking and heating are apt to be more troublesome. An object of my invention is to provide an improved relatively high contact pressure and economical switch construction in which heating and sticking effects are minimized and the parts are not subjected to unnecessarily large stresses. A further object is to provide ease of operation for high voltage and for high current capacity switches.

My invention will be better understood from the following description when considered in connection with the accompanying drawings and its scope will be pointed out in the appended claims.

In the'accompanying drawings, Fig. 1 is :5 a vertical side elevation of a switch embodying my invention and shown in the circuit open position; Fig. 2 is a vertical front elevation to a larger scale of the switch shown in Fig. 1 with the blade in the circuit closing position prior to contact engagement; Fig. 3 is a partial elevation similar to Fig. 2 showing the blade in circuit closlng' position after contact engagement.

In the electric switch which I have chosen to illustrate my invention, a movable conducting element such as a switch blade 4 is pivotally mounted on a support such as a hinge clip 5 secured to a fixed insulator 6. The conductor or blade 4 is provided at one end, that is the free end, with one or more lator 9 is provided with one or morelugs or jaws 10 which, as shown, are substantially rigid and are arranged to be engaged by the free end of the blade. As shown, the free end of the blade, comprising the relatively long movable portions 7, is movable into position between the jaws or contact elements 10 on angular movement of the blade in one direction, that is circuit closing direction. The contact 8 may, if desired, comprise an integral terminal portion 11. The opposed faces or contact surfaces of the contact jaws 10 are preferably convex in order to provide a contact in the nature of a line to line engagement. A hood 12 "may be provided to shield the contact 8 from snow, sleet and the like.

In accordance with my invention, I provide means which is adapted to be actuated to effect relative movement of the blade portions 7 whereby to force them against the respective contact jaws 10 as the blade 4 is moved to the circuit closing position. As shown, this forcing means is arranged to separate or spread the blade portions 7 so as to eifect a relatively high pressure contact between them and the contact jaws 10. The forcing means may be of any suitable type whereby to obtain the desired mechanical advantage. In the illustrated embodiment of my invention, the forcing means is of the inclined plane type and includes a wedge 13 mounted for movement relatively to the blade and between the end portions 7 thereof. To the blade portions 7 are secured cooperating shoes 14 with suitably sloping faces between which the wedge 13 moves to obtain the desired spreading action and thereby a relatively heavy contact pressure. The wedge 13' may be secured to or form a part of an actuating member 15 which moves with the blade and is supported thereby in part by a pin 16 extending through the blade and a lost motion slot in the memher.

For releasing the pressure on the blade portions 7 when it is desired to open the switch, the actuating member 15 is biased for movement from the stationary contact 8 by any suitable means such as a relatively strong spring 17 which may bemounted In a housing 18 of an element 19 which cooperates with the operating member 15. For operating the member 15 through the sprin 17, the element 19 may be a plunger carrie by the blade 4 by suitable means such as a pin 20 which extends through the blade and a lost motion slot in the plunger. This plunger 19 is arranged to work in a cylindrical portion of the actuating member 15, as shown, so as to have a limited movement therein. The plunger is secured to the actuating member 15 by a pin 21 extending through the cylindrical portion thereof and a lost motion slot in the plunger. In order to allow for variations in movement and to obtain thedesired contact pressure, a relatively stiff spring 22 is mounted in the cylindrical portion of the operating member 15 to abut the plunger 19.

I For opening and closing the switch, I provide a switch operating means including a movable member such as a rotatable arm or crank 23 arranged on movement in one direction, counter clockwise as shown in Fig. 2, to move the free end of the blade, that is the blade portions 7, into position between the contact jaws 10 and on further movement in the same direction to actuate the forcing means or wedge 13 so as to effect contact engagement at the desired pressure. As shown, the crank 23 is connected to the plunger 19 through a link 24 and a lever 25 pivotally secured to the blade 4 at 26 and to the plunger 19 at 27. The crank 23 is ar ranged to move with a rotatable insulator 28 which is mounted in line with the fixed insulators 6 and 9. This rotatable insulator is arranged to be actuated in any suitable manner as by a crank 29 secured to a mov able rod 30 which connects all the rotatable insulators of a multiple pole switch so as to obtain simultaneous movement thereof. For stiffening purposes, a bridging member 31 may be used to connect the insulators 6 and 28 and to provide an upper bearing for the rotatable insulator 28. This bridging member 31 may also, as shown, be an integral part of the hinge clip 5 and include the other switch terminal 32. In this way it is possible to dispense with a flexible or pigtail connection between the switch blade 4 and the terminal 32.

In order to maintain the blade portions 7 in engagement with the contact jaws 8 against the bias of the spring 17, I provide means for restraining the wedge 13 in a position to maintain the pressure between the blade portions 7 and the contact jaws 8. As shown, this restraining means is of the toggle type and comprises the crank 23 and the link 24 whose common pivotal connection 33 is arranged to pass over the center in the final closing movement and is held-in the overset position by a projection 34 on the crank 23 which engages a stop 35 preferably adjustably mounted on the terminal end 32 of the bridging member 31.

For the operation of the illustrated embodiment of my invention, it will be assumed that the switch is in the circuit open position as shown in Fig. 1 and that the rotatable insulator 28 is rotated counter-clockwise, with reference to Fig. 2, or with reference to Fig. 1 that the crank 29 is moved backward from the plane of the drawings. In this case the linkage comprising the crank 23 and the link 24 will be lengthened and the blade 4 through the lever 25 will be turned counter-clockwise with reference to Fig. 1 into the position shown in Fig. 2 with the blade portions 7 resting on the. base of the contact 8 adjacent the jaws 10. During this angular movement of the blade, the operating member 15 will not be moved to cause the wedge 13 to spread the blade portions since the pressure exerted by the spring 17 in its expanded position between the pin 20 and the base of the plunger 18, as shown in Fig. 2,.is greater than the force to be overcome in moving the blade down on to the base of the contact 8. On further rotation of the insulator 28 in the same direction, that is counter-clockwise, with reference to Fig. 2 the linkage comprising the crank 23 and the link 24 will be further lengthened and the lengthening thereof taken up by movement of the lever 25 about its pivot 26. In this movement of the lever 25, the plunger 19 will be moved toward the stationary contact 8 thereby causing the wedge 13 to move forward between the narrow part or converging, sides of the shoes 14 so as to force the blade portions 7 against the contact jaws 8 as shown in Fig. 3. In this movement the end portions 7 are flexed and both of the springs 17 and 22 are compressed. \Vhen the crank 23 passes over the center, the projection 34 engages the stop 35 to hold the toggle comprising the crank 23 and link 24: in the overset position as shown in dotted lines in Fig. 2. This prevents the springs 17 and 22 from releasing the wedge 13 and maintains the desired high pressure contact which together with the tog le'restraining action helps to prevent the b ade from flying open under the magnetic stresses which accompany the passage of heavy currents through the switch.

The operation of opening the switch is the reverse of that just described for closing. The insulator 28 is rotated clockwise with reference to Figs. 3 and 2. In movement the toggle is first moved back over the center and lit tions 7, the springs 17 and 22 accelerating.

this movement. When the motion permitted by the lost motion slots in the blade 4 and the plunger 19 is completed, further rotation of the lever 25 in the clockwise direction with reference to Fig. 1 is prevented and continued clockwise rotation of the insulator 28, with reference to Fig. 2, effects themovement of the blade about its hinge clip or ivot into the circuit open position shown in ig. 1.

While I have shown and described my invention in considerable detail I do not desire to be limited to the exact arrangement shown,

but seek to cover in the appended claims all those modifications that fall within the true spirit and scope ofmy invention.

What I claim asnew and desire to secure by Letters Patent of the United States is:

1. In a disconnecting switch, two fixed insulators, a blade pivotally mounted on one of said fixed insulators for movement in the plane of said insulators and provided at the free end with two portions movable relatively to each other transversely of the plane of movement of the blade, a cooperating contact mounted on the other fixed insulator and having two spaced jaws into which said portions are movable on movement of the blade in one direction, a stop, means mounted 011 said blade movable relatively thereto for elfecting relative movement of said portions transversely of the blade whereby to force them against said jaws and biased for movement in a direction to release the pressure between the portions and the jaws, switch operating means for actuating said blade including a rotatable insulator mounted in line with said fixed insulators and arranged on rotation in one direction to move the free end of the blade against said stop into position between said jaws and on further rotation in the same direction to actuate said forcin means whereby to force said portions against said jaws and means for restraining said forcing means in a position to maintain the pressure between said portions and said jaws.

2. In an electric switch, the combination of a supporting insulator, two fixed contact elements mounted on said insulator, a second supporting insulator, a support mounted thereon, a conductor pivotally mounted on said support, said conductor comprising two relatively long spaced conducting portions, an actuating member mounted between said conducting portions, one end of said actuating member being constructed and arranged to be operable on movement in one direction to spread said conducting portions and operating means connected to said actuating member operable in one direction to rotate said actuating member and said conductor about the pivotal support thereof until said conducting portions rest between said contact elements and on further movement in the same direction to move said actuating mem ber in the direction to force said conducting portions against said contact elements.

3. In an electric switch, the combination of a supporting insulator, two fixed contact elements mounted on said insulator, a second supporting insulator, a support mounted thereon, a conductor ivotally mounted on said support, said con uctor comprising two relatively long spaced conducting portions,

an actuating member mounted between said conducting portions, one end of said actuatmg member being constructed and arranged to be operable on movement in one direction to spread said conducting ortions, operatmg means connected to said actuating member operable in one direction to rotate said actuating member and said conductor about the pivotal support thereof until said conducting portions rest between said contact elements and on further movement in the same direction to move said actuating member in the direction to force said conducting portions against said contact elements, and means for restraining said actuating member in position to mamtainthe pressure between said conducting portions and said contact elements.

4. In an electric switch, the combinationof a supporting insulator, two fixed contact elements mounted on said insulator, a second supporting insulator, a support mounted thereon, a conductor pivotally mounted on said support, said conductor comprising two relatively long spaced conducting portions, an actuating member mounted between said conducting portions, one end of said actuating member being constructed and arranged to be operable on movement in one directlon to spread said conducting portions, operating means connected to said actuating member operable in one direction to rotate said actuating member and said conductor about the pivotal support thereof until said conducting portions rest between said contact elements and on further movement in the same direction to move said actuating member in the direction to force said conducting portions against said contact elements, and means for biasing said actuating member for movement in a direction to release the pressure of said conducting portions against said contact elements.

5. In an electric switch, the combination of a supporting insulator, a jaw contact mounted on said insulator, a second supporting insulator, a support mounted thereon, a conductor pivotally mounted on said support, said conductor comprising two yieldingly spaced blades, an actuating member mounted between said blades, said actuating member being constructed and arranged to be operable on movement of the member in one direction to spread said blades,-operating means connected to said actuating member operable in one direction to rotate said actuating mem- 5 her and said conductor about the pivotal support thereof until said blades rest between t e aws of said contact and on further movement in the same direction to move said actuating member in a direction to force said blades against the jaws of said contact.

6. In an electric switch, the combination of a supporting insulator, two fixed contact elements mounted on said insulator, a second supporting insulator, a support mounted thereon, a conductor pivotally mounted on said support, said conductor comprising two relatively long spaced blades, shoes mounted on the opposing faces of said blades adjacent the free ends thereof, an actuating g member mounted between said blades for movement about the pivotal support of said conductor, Wedging means on said member cooperating with said shoes on movement of the actuating member in one direction to 51,5 spread said blades and operating means connected to said actuating member operable in one direction to rotate the member and said conductor about the pivotal support thereof until said blades rest between said contact elements and on further movement in the same direction to move said actuating member in the direction to cause said wedging means to force said blades against said contact elements. In witness whereof I have hereunto set my hand this 5th da-v of March, 1928.

FREDERICK E. FISHER. 

